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Updated: Jun 29, 2025

Dissecting Innate Immune Signaling in Viral Evasion of Cytokine Production
Published on: March 2, 2014
Langat virus inhibits the gp130/JAK/STAT signaling by reducing the gp130 protein level
Shaoli Lin1, Xiaochun Wang1, Bhargava Teja Sallapalli1
1Molecular Virology Laboratory, Virginia-Maryland College of Veterinary Medicine, University of Maryland, College Park, MD, USA.
Abstract:
The tick-borne encephalitis virus (TBEV) serocomplex includes several medically important flavivirus members endemic to Europe, Asia, and North America, which can induce severe neuroinvasive or viscerotropic diseases with unclear mechanisms of pathogenesis. Langat virus (LGTV) shares a high sequence identity with TBEV but exhibits lower pathogenic potential in humans and serves as a model for virus-host interactions. In this study, we demonstrated that LGTV infection inhibits the activation of gp130/JAK/STAT (Janus kinases (JAK) and signal transducer and activator of transcription (STAT)) signaling, which plays a pivotal role in numerous biological processes. Our data show that the LGTV-infected cells had significantly lower phosphorylated STAT3 (pSTAT3) protein upon oncostatin M (OSM) stimulation than the mock-infected control. LGTV infection blocked the nuclear translocation of STAT3 without a significant effect on total STAT3 protein level. LGTV inhibited JAK1 activation and reduced gp130 protein expression in infected cells, with the viral NS5 protein mediating this effect. TBEV infection also reduces gp130 level. On the other hand, pretreatment of Vero cells with OSM significantly reduces LGTV replication, and STAT1/STAT2 knockdown had little effect on OSM-mediated antiviral effect, which suggests it is independent of STAT1/STAT2 and, instead, it is potentially mediated by STAT3 signlaing. These findings shed light on the LGTV and TBEV-cell interactions, offering insights for the future development of antiviral therapeutics and improved vaccines.
Insights
Langat virus (LGTV) and tick-borne encephalitis virus (TBEV) inhibit gp130/JAK/STAT signaling pathways. This viral interference impacts host cell responses and offers targets for novel antiviral therapies and vaccines.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- Tick-borne encephalitis virus (TBEV) serocomplex causes severe neuroinvasive diseases.
- Langat virus (LGTV), a TBEV relative, models virus-host interactions with lower pathogenicity.
- gp130/JAK/STAT signaling is crucial for biological processes and immune responses.
Purpose of the Study:
- To investigate the effect of LGTV infection on gp130/JAK/STAT signaling.
- To elucidate the role of viral proteins in modulating this pathway.
- To explore potential antiviral strategies based on these interactions.
Main Methods:
- Assessing STAT3 phosphorylation and nuclear translocation in LGTV-infected cells stimulated with oncostatin M (OSM).
- Measuring JAK1 activation and gp130 protein expression in infected cells.
- Evaluating the impact of LGTV NS5 protein and TBEV infection on gp130 levels.
- Investigating the antiviral effects of OSM pretreatment and the role of STAT1/STAT2.
Main Results:
- LGTV infection significantly reduced phosphorylated STAT3 (pSTAT3) levels and blocked STAT3 nuclear translocation upon OSM stimulation.
- LGTV inhibited JAK1 activation and decreased gp130 expression, mediated by the viral NS5 protein.
- TBEV infection also led to reduced gp130 levels.
- OSM pretreatment inhibited LGTV replication, suggesting a STAT3-mediated antiviral mechanism independent of STAT1/STAT2.
Conclusions:
- LGTV and TBEV interfere with the gp130/JAK/STAT signaling pathway.
- The viral NS5 protein plays a role in downregulating gp130 expression.
- OSM-induced antiviral effects appear to be mediated by STAT3 signaling.
- Understanding these virus-host interactions provides a basis for developing new antiviral treatments and vaccines against TBEV and related flaviviruses.
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